1. Field of the Invention
The present invention relates to a device and a method for detecting the rotational movement of an element which is rotatably seated around an axis, in particular a turntable.
2. Discussion of Related Art
The detection of the rotational movement takes place for the purpose of determining deviations from an ideal rotational movement around a predetermined axis. For example, this can be a so-called calibrating measurement, wherein the detected deviations of a rotational movement from an ideal rotational movement can be used for a subsequent calibration. This means that the knowledge of the deviations from an ideal rotation which have occurred can be taken into consideration by calculation in the course of a subsequent use of the rotationally seated element, for example a turntable or a machine tool spindle.
The deviations of the rotational movement of a turntable or other rotationally seated element from an ideal rotational movement around a predetermined axis can be separated into six individual deviations, namely respectively three translatory and rotary deviations.
A method and a device for measuring turntable deviations are known from DE 36 37 410 C2, wherein the turntable is arranged within the measuring volume of a coordinate measuring device, and the deviations are detected with the aid of the coordinate measuring device in that a test member is fastened on the turntable, which has a multitude of measuring points formed by contact faces, and that respective sets of measuring point coordinates are measured by the coordinate measuring device by means of contact in various angular positions of the turntable. The turntable deviations are calculated by means of these sets of measuring points. This method has the disadvantage that contact with the test member is required and that the individual deviations can only be determined in a sequence of several measurements.
A method for measuring the deviation of rotating axes by means of test spheres or test cylinders is described in the reference “Werkzeugmaschinen und Fertigungssysteme” [Machine Tools and Production Systems], vol. 4, VDI publishers, 1996, p. 149 et seq. The methods mentioned there have the disadvantage, however, that each only permits the measuring of a portion of the six individual deviations.